1. Field of the invention
The present invention relates to a vehicle including a body frame that leans and two wheels that are aligned side by side in a left-to-right direction.
2. Description of the Related Art
In recent years, the usefulness of small vehicles has begun to be recognized in urban areas of countries where traffic jams are getting more severe. Small vehicles now tend to be supported widely for economic and environmental reasons. As an example of a small vehicle, there is known a three-wheeled motor vehicle like the one described in International Patent Publication No. 2014/098228 which includes two front wheels.
In general, the vehicle including the body frame that leans and the two wheels that are aligned side by side in the left-to-right direction is a vehicle that is able to turn with the body frame leaning from a vertical direction. More specifically, the body frame leans to the right of the vehicle when the vehicle turns right, whereas when the vehicle turns left, the body frame leans to the left of the vehicle. In the vehicle including the body frame that leans and the two wheels that are aligned side by side in the left-to-right direction, a distance defined between the two wheels that are aligned side by side in the left-to-right direction of the body frame is narrower than that of a general four-wheeled vehicle so as to ensure that the body frame leans as required. The vehicle including the two wheels that are aligned side by side in the left-to-right direction and the body frame that leans is a vehicle that is compact in size in the left-to-right direction.
As this type of vehicle, a vehicle described in PARTS CATALOGUE MW125 (2CM1), YAMAHA MOTOR CO. LTD. is now on market. The vehicle described in PARTS CATALOGUE MW125 (2CM1), YAMAHA MOTOR CO. LTD. includes a power unit including an internal combustion engine which produces a driving force by which the vehicle is driven. The engine mounted on the vehicle described in PARTS CATALOGUE MW125 (2CM1), YAMAHA MOTOR CO. LTD. is a relatively small engine having a displacement of 125 cc. A power unit having such a small engine is advantageous in that it is light in weight and has a superior fuel economy.
However, when wanting to travel a long distance comfortably, it is sometimes found that a vehicle with an engine of a large displacement is advantageous. The inventor of the present invention studied the possibility of a large power unit being mounted on the vehicle described in PARTS CATALOGUE MW125 (2CM1), YAMAHA MOTOR CO. LTD. that includes the body frame that leans and the two front wheels. The inventor thought that the acceleration performance increases as the displacement of a power unit increases, increasing the comfortability when traveling a long distance. Then, a load acting on a link support of the vehicle increases as the acceleration performance increases. In the event that the load acting on the link support increases, the rigidity required of the link support increases. However, when attempting to enhance the rigidity of the link support, it is assumed that the body frame increases in size.